Magnet

Abstract

Magnets and systems, methods, and techniques for manufacturing magnets are provided. In some embodiments, methods of manufacturing magnets comprise providing a rare earth magnetic body, depositing a bead of dysprosium or terbium metal onto a part of the magnetic body to form a magnet; and heat-treating the magnet. In some embodiments, a magnet is provided comprising a magnetic body and a bead of dysprosium or terbium metal. In some embodiments, the magnetic body contains grains of rare earth magnet alloy, and the bead of dysprosium or terbium metal is deposited onto a part only of a surface of the magnetic body.

The invention claimed is: 
     
       1. A method of manufacturing a magnet, the method comprising:
 providing a magnetic body containing grains of a rare earth alloy, wherein a surface of the magnet body is geometrically divided by pole intersections; 
 depositing a bead of dysporium metal onto a region farthest away from the pole intersections of the magnetic body via a cold spray process to form a magnet; and 
 heat-treating the magnet. 
 
     
     
       2. The method of  claim 1 , wherein the magnetic body comprises a plurality of poles, and depositing a bead of dysprosium metal comprises depositing a bead of dysprosium metal onto a part only of a surface of each of the poles. 
     
     
       3. The method of  claim 1 , wherein each metal bead is deposited at the edge of the magnet body surface. 
     
     
       4. The method of  claim 1 , wherein heat-treating the magnet comprises a grain boundary diffusion process. 
     
     
       5. The method of  claim 1 , wherein heat-treating the magnet comprises:
 heating the magnet to a first elevated temperature; 
 cooling the magnet to second temperature; and 
 quenching the magnet to room temperature. 
 
     
     
       6. The method of  claim 5 , wherein the first elevated temperature is at least 900° C. 
     
     
       7. The method of  claim 5 , wherein the second temperature is at least 500° C. 
     
     
       8. The method of  claim 5 , wherein the composite magnet is held at the first elevated temperature for at least 6 hours. 
     
     
       9. The method of  claim 5 , wherein the composite magnet is held at the second temperature for at least 0.5 hours. 
     
     
       10. The method of  claim 1 , wherein the rare earth alloy is a neodymium alloy. 
     
     
       11. The method of  claim 10 , wherein the neodymium alloy is Nd 2 Fe 14 B. 
     
     
       12. A magnet comprising a magnetic body and one or more beads of dysprosium metal; wherein the magnetic body has a surface that is geometrically divided by pole intersection and contains grains of rate earth magnet alloy, and wherein each bead is deposited onto a region farthest away from the pole intersections via a cold spray process. 
     
     
       13. The magnet of  claim 12 ; wherein each metal bead is deposited at the edge of the magnet body surface. 
     
     
       14. The magnet of  claim 12 ; wherein the magnet is cylindrical in shape. 
     
     
       15. The magnet of  claim 12 , wherein the magnetic body is a sintered rare earth magnet. 
     
     
       16. The magnet of  claim 12 , wherein the rare earth alloy is a neodymium alloy. 
     
     
       17. The magnet of  claim 16 , wherein the neodymium alloy is Nd 2 Fe 14 B. 
     
     
       18. The magnet of  claim 12 , wherein an amount of dysprosium is diffused within the grains. 
     
     
       19. The magnet of  claim 18 , wherein the grains contain an amount of diffused dysprosium of between 0.5 to 15 percent by weight. 
     
     
       20. The magnet of  claim 18 , wherein the dysprosium is diffused along the boundaries of the grains to form a shell layer. 
     
     
       21. The magnet of  claim 20 , wherein the magnetic body comprises grains of Nd 2 Fe 14 B with a shell layer comprising Dy 2 Fe 14 B or (Dy,Nd) 2 Fe 14 B. 
     
     
       22. The magnet of  claim 20 , wherein the shell layer has a thickness of about 0.5 μm. 
     
     
       23. The magnet of  claim 12 , wherein the deposition thickness of the bead of dysprosium metal is between 1 to 5 μm.